https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112927
Bug ID: 112927
Summary: -Wanalyzer-tainted-size false positive seen in Linux
kernel's drivers/char/ipmi/ipmi_devintf.c
Product: gcc
Version: unknown
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: analyzer
Assignee: dmalcolm at gcc dot gnu.org
Reporter: dmalcolm at gcc dot gnu.org
Blocks: 106358
Target Milestone: ---
Created attachment 56837
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56837&action=edit
Reduced reproducer
With the kernel plugin, this test erroenously reports:
In function 'call_copy_from_user',
inlined from 'handle_send_req' at
gcc.dg/plugin/taint-drivers-char-ipmi-ipmi_devintf.c:35:7:
gcc.dg/plugin/taint-drivers-char-ipmi-ipmi_devintf.c:19:7: warning: use of
attacker-controlled value as size without upper-bounds checking [CWE-129]
[-Wanalyzer-tainted-size]
19 | n = copy_from_user(to, from, n); /* { dg-bogus "use of
attacker-controlled value as size without upper-bounds checking" } */
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~
'ipmi_ioctl': events 1-4
|
| 41 | ipmi_ioctl(void* arg)
| | ^~~~~~~~~~
| | |
| | (1) entry to 'ipmi_ioctl'
|......
| 44 | if (call_copy_from_user(&msg, arg, sizeof(msg))) {
| | ~
| | |
| | (2) following 'false' branch (when 'n == 0')...
|......
| 48 | return handle_send_req(&msg);
| | ~~~~~~~~~~~~~~~~~~~~~
| | |
| | (3) ...to here
| | (4) calling 'handle_send_req' from 'ipmi_ioctl'
|
+--> 'handle_send_req': events 5-8
|
| 29 | handle_send_req(struct ipmi_msg* msg)
| | ^~~~~~~~~~~~~~~
| | |
| | (5) entry to 'handle_send_req'
|......
| 32 | if (msg->data_len > 272) {
| | ~
| | |
| | (6) following 'false' branch...
|......
| 35 | if (call_copy_from_user(buf, msg->data, msg->data_len)) {
| | ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| | |
| | (7) ...to here
| | (8) inlined call to 'call_copy_from_user' from
'handle_send_req'
|
+--> 'call_copy_from_user': event 9
|
| 19 | n = copy_from_user(to, from, n); /* { dg-bogus
"use of attacker-controlled value as size without upper-bounds checking" } */
| | ^~~~~~~~~~~~~~~~~~~~~~~~~~~
| | |
| | (9) use of attacker-controlled value as size
without upper-bounds checking
|
despite the value being sanitized at event (6).
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=106358
[Bug 106358] [meta-bug] tracker bug for building the Linux kernel with
-fanalyzer
